What you are failing to realize is that the fact that it was publicly available doesn't make it legal for him to use something that isn't his. A lot of copyrighted material is available publicly. That doesn't make it legal to posess or use, especially when it's potentially for profit (on a forum that hosts ads, for instance.)

He stole someone elses work, even though it wasn't from the source, and then threatened to release the knowingly stolen material to his members if Chruser didn't submit to his desires. He's an asshole. Which probably makes him perfect for these forums, but unbanning him isn't going to bring him back anyway.